science club

2009-10-25T20:49:00.001-07:00

Rencana Bisnis Internet Dari Nol (bag 1)

2009-10-25T20:47:00.000-07:00

2009-09-08T19:38:00.000-07:00

benefits of food for the human body

2009-08-26T20:40:00.000-07:00

How Phytonutrients and Bio-Energy Benefit the Human Body

(Natural News) There is much talk about phytonutrients lately. What are phytonutrients and why are they so important? Well simply put, phytonutrients are certain compounds found in plants that evidence has shown to increase overall health and protect against certain diseases including cancer. The term “Phyto” comes from the Greek work for plant so phytonutrients are plant nutrients, though they’re of a different class then the traditional nutrients of fats, proteins, vitaminsand minerals.

These nutrients are not considered “essential for life” but they are important for health and longevity. Fruits, vegetables, grains, legumes, nuts, and teas are rich sources of phytonutrients. Fruits and vegetables that are high in carotenoids appear to protect humans against certain cancers, heart disease, and age-related macular degeneration.

So what does this have to do with bio-energy? Everything actually. Bio-energy is the actual energy source of the body that keeps you alive every second. Science knows that the body not only uses and generates electricity but also electromagnetic energy. The Chinese call this energy Chi. It is derived and absorbed from nature including the Sun, moon, stars, heavens, the earth, and most importantly from the air itself, also known as ionic energy.

Plants absorb this energy as they grow in the ground from the earth and absorb this energy from the sun and transfer it to their fruits. We then consume this energy when we eat the fruits which is extracted from the food during digestion via the spleen, something that it little known in western medical circles.

That is why these nutrients from natural plant sources are so important and beneficial to human health and longevity. It’s the same reason why drinking herbal and natural teas are so popular in China which has the greatest number of centenarians (people who live to be one hundred years old or older) in the world.

All processes in the body require energy, just like any chemical reaction does in chemistry. We get this energy from the foods that we eat and the air we breathe. The body also must have enzymes to break food down, kill viruses, bacteria, dissolve tumors and even to break down and build up muscle tissue and everything else in the body. A diet of at least fifty percent raw, unprocessed foods is vital to make sure that we're getting enough enzymes, phytonutrients, and the all important Chi or bio-energy for the body's processes to function optimally.

Some of the main sources of phytonutrients are as follows: Carrots, leafy green and yellow vegetables (e.g. broccoli, sweet potato, pumpkin, and carrots), peaches, apricots, leafy greens such as kale, spinach, turnip greens, tomato products, pink grapefruit, watermelon, guava, green vegetables, eggs, citrus.

I take food enzymes with every meal to aid digestion. This also takes a big load off the pancreas which makes most of the enzymes in the body. The more live, unprocessed food that we eat; the more phytonutrients, enzymes and bio-energy we take in. All natural foods contain this all important bio-energy or chi and without it no life could exist. This is how these foods help to increase our immune system, health, strength and regeneration of the body itself and ultimately help us feel better and live longer.

So to boost your own immune system and cell regeneration of the body, eat more phytonutrients, practice deep breathing exercises daily and make sure that your diet is at least fifty percent raw, unprocessed natural foods (preferably organic whenever possible) and you too can soon be singing the praises of phytonutrients.

Grape Seed Extract: Benefits to the Human Body

The food supplement known as grape seed extract is taken from the seeds and skins of red grapes. For those of you who are unsure of the various types of grapes that are on the market, this is the type that’s generally used in the production of wine.

This is a very popular food supplement in Europe and is considered by some to be more effective than Vitamin C and Vitamin E in its response to the body’s needs, since its rich in flavonoids – which contain powerful antioxidant properties. Among the most effective of these flavonoids are PCOs (procyanidolic oligomers). These PCOs, which are present in the grape seed extract food supplement, also help to improve blood circulation and provide strengthening of the vessels.

Health Benefits
Prescribed by doctors in Europe for a variety of vascular disorders, grape seed extract is of some benefit to heart and cancer patients, when the food supplement is administered regularly. Grape seed extract also helps to reduce or eliminate the symptoms of leg cramps, varicose veins, diabetes, numbness in the extremities – an even the effects of impotence, since this food supplement is designed to improve the body’s blood flow.

Other benefits of grape seed extract are in the areas of endometriosis, since the effects of this can be inhibited by the food supplement’s ability to provide antioxidants that can also invade the membranes of the body. Brain cells may also be protected from certain forms of damage (known as free radical damage) when grape seed extract is administered.

For those who are interested in retaining a youthful appearance, the benefits of grape seed extract come into play, as well. This versatile food supplement helps to maintain the elasticity of the skin, and is a popular ingredient of many facial and skin creams.

In countries such as America, where heart disease is prevalent, there’s a great deal of need for products that prevent such illnesses. Grape seed extract is outstanding in its ability to maintain healthy heart performance, due to its ability to prevent the development of plaque, which is known to clog the arteries and endanger those who suffer from this condition. Stroke can also be avoided through the ongoing use of this particular food supplement, for the same reasons.

High cholesterol is another major health concern in some parts of the world today – including America – and the call for agents that can reduce cholesterol is ongoing. Grape seed extract can be used to replace regular cooking oils, and has been known to reduce cholesterol levels by up to 14% in the span of one month.

Other health benefits that are derived from this food supplement include the minimization of fibromyalgia, occurrences of cancer, and the skins ailments known as eczema and psoriasis. Additional health areas that are improved through the use of grape seed extract are eyesight – the effects of macular degeneration and cataracts are diminished; allergic reactions – this food supplement provides a natural antihistamine and anti-inflammatory; and many other illnesses.

A food supplement in the form of grape seed extract is known to be quite safe and is effective in the treatment of a wide number of illnesses. Currently, grape seed extract can be purchased in the form of liquid, tablet or capsule

ORGANIC FOOD

Is good nutrition important in your life? For me, it is one of the most important issue because good nutrition signifies better life in general. One of the main ways to improve your food products is buying organic products. In our time pesticides are part of our every day life. This is sad. But you have the power to make choices. One of them is refusing to have food products which were bombarded with insecticides and pesticides to name only a few.

Think about all the food or other things you put in your body. What do you eat on a regular basis? Are you a fast-food nut, or do you take the time to prepare healthy meals at home? This question is a crucial one simply due to the fact that you are what you eat. Now, this can be interpreted in many ways. Clearly I don't mean that if you consume McDonald's every day, you're a Big Mac. But, if you do resort to fats-food that often, you should be concerned with your health. There is a reason why some healthy nuts are totally into organic products and won't touch restaurant cuisine. It's time you got in-the-know.

About two years ago, I began purchasing organic products. It's not that I was eating horrible foods in the past, but I wanted to pass on to my children a healthier lifestyle. I pretty sure that everyone wants their children to live a healthy life. My wife finally agreed to join me in my organic food products crusade after a while. So we started shopping for groceries at a finer food market. You know, the ones that focus on organic products and superb cuts of meat. Now, just to be clear, this is of course a more costly way to shop. Most organic farmers don't have the major earnings that the rest of them do. They earn less capital because they are providing on a smaller scale.

A dairy farmer shooting his cattle full of hormones can clearly produce much more milk than a farmer who goes the natural route. So in short, organic products cost more. But hey, you get what you pay for. Now, you may wonder why you should care if you're consuming organic products or not. This is a simple one. When you eat foods such as dairy products and meat that are not organic, you're also eating loads of antibiotics and hormones that have been given to the animals. This is not good for your body, and it seems that it leads to cancer.

Think about making the switch. You may want to pick up a few items that you eat regularly, which are organic if you're not willing to buy organic products only. This way the cheese or milk you consume on a regular basis will not be damaging your system with unnatural hormones, which can seriously affect the growth rate of your kids. Teach them a healthy lifestyle by buying organic products. You will be rewarded with abetter health if you have good eating habits on the long run which will translate in a happier life. Go the organic products route and be happy!

RAW ORGANIC SPROUTS

It's easy to grow your own organic sprouts at home. Select the seed of your choice, soak in chemical free solution, drain after 24-48 hours and rinse with filtered water. The health advantages of adding raw organic sprouts have been well documented over the years. See list of a few popular seeds you can sprout.

(Radish, Celery, Cauliflower, Mustard, Peas, Wheat, Alfalfa, Soybean, Garlic, Onion and Cabbage)

Many health professionals agree that sprouts can offer your body important nutrients. Some of these nutrients are the building blocks of life and provide numerous health benefits for a several functions of the body. Vitamins, minerals and amino acids a few of the building blocks. If you sprout in an organic environment, the seeds will sprouts will not have any harmful chemicals. This will help reduce the intake of toxic chemicals into the body.

Dietitians and doctors agree that the consumption of organic sprouts is safe and effective while incorporating raw foods into your lifestyle. Eating a diet consisting of raw foods is less likely to cause any experience of such illness, disease as well as other uncomfortable conditions. A very successful aspect for this type of diet is the consumption of organic sprouts. The consumption of these types of foods, aid in losing weight, as well as preventing different types of cancers and preventing heart disease, which are all beneficial to good health.

Did you know you could do your own sprouting when you enjoy eating the raw foods of nature? Many people enjoy sprouting their own seeds. Sprouting your own seeds is helpful as you can sprout your own seeds while saving a great deal of money, without having to buy sprouts someone else processed. The Easy-Sprouter is one item that is most helpful when you begin your own organic sprouting. Even if you have no experience with organic sprouting, the Easy-Sprouter is effective and wallet friendly. One of the best benefits of using an Easy-Sprouter is that you do not have to have any experience to use it and it does not require you to rinse the seeds.

The Easy-Sprouter establishes an ideal growing environment for an assortment of seeds. This environment removes the need to have experience in organic sprouting. Not only are you saving time and money while using the Easy-Sprouter, but you will also be making a practical contribution to our environment.

Stem-cell Genes That Help Form Plant Organs Identified

2009-08-24T20:07:00.000-07:00

Stem-cell Genes That Help Form Plant Organs Identified
ScienceDaily (Mar. 6, 2009) — Plant stem-cells are master cells located at the tip of the stem and are part of a structure called the shoot apical meristem (SAM). Here, the stem cells—all clumped together—divide throughout the life of the plant to give rise to other cells, resulting in the formation of above-ground organs such as leaves, flowers, branches and stem.
But despite the important role the stem cells play in plant development, their molecular composition has eluded researchers for long.
Now, working on Arabidopsis, a mustard-like plant that is a model for studying plant biology, a team of researchers at UC Riverside has identified all the genes expressed in the plant's stem cells.
The researchers also identified all the genes expressed in two other SAM cells: niche cells (which are located just beneath the stem cells and which provide signals that regulate the stem cells), and differentiating cells (which are generated by, and surround, the stem cells).
The final product of the researchers' work is a genome-scale, expression map of SAM—an achievement that paves the way to developing better varieties of crops and plants.
Besides revealing the molecular pathways that stem cells employ, the discovery also can help scientists better understand why stem cells—in both plants and animals—give rise to specialized cells at all.
Study results appear online this week in the early edition of the Proceedings of the National Academy of Sciences.
"Our study is the first to reveal the stem-cell signatures for any plant and the first to provide a global view of which genes are expressed, and where, within the SAM," said G. Venugopala Reddy, the lead author of the study and an assistant professor of plant cell biology in the Department of Botany and Plant Sciences. "Since SAM stem-cells are responsible for forming plant organs and determining plant architecture, further analysis of their genes may provide a handle in altering growth rates and growth patterns in economically important crop-species in order to maximize yield."
Reddy stressed that understanding the function and regulation of stem-cell-specific genes is critical to gaining insights into basic questions such as what constitutes stem-cell identity (the ability of cells to remain unspecialized) and what makes them differentiate into specialized cells.
"A comparative analysis of stem-cell-specific genes between plant and animal systems may also lead to a better understanding of stem-cell identity, a concept common to both the systems," he said.
The study breaks ground also in the way Reddy's research team pinned down the stem-cell genes in Arabidopsis.
His lab initially labeled the three different SAM cell types—stem cells, niche cells and differentiating cells—by using different fluorescent proteins. Next, the researchers isolated the three discrete cell populations by first stripping the cell walls to release the cells as free populations. Then, using an instrument called Fluorescence Activated Cell Sorter, they separated each set of cells from the rest of the cell populations.
"Plant biologists have found it difficult to isolate the approximately 35 stem cells in the Arabidopsis shoot system for two main reasons: this is an extremely low number of stem cells and this clump of cells is tightly packed with a waxy coating covering its outer layer," Reddy said. "To meet this challenge, we used specific mutants of Arabidopsis that make more SAMs per plant. In the lab, we also formulated specific combinations of enzymes that efficiently digest away the cell walls."
Reddy explained that the gene expression map his team generated can help researchers track how genes give rise to complex tissues. It also will allow researchers to determine the expression patterns of SAM genes by a mere click of a button on a computer.
"Development of an organ such as SAM is a complex process in which cells constantly exchange information through regulated gene activities," he said. "What we have done so far is to find out which genes are expressed and where. One of the future challenges is to represent the gene expression on actual templates of plant cells, which would generate a dynamic atlas of stem-cell development. Such an atlas can be used to explore how genes function as a network to bring about stem-cell function."
Reddy acknowledged that developing the atlas is a difficult venture, requiring a synthesis of multiple disciplines such as genomics, live-imaging and informatics sciences.
"But our work breaks ground to make this a reality and we have already initiated some work in this direction," he said.
Reddy, who is also a member of UCR's Center for Plant Cell Biology, was joined in the research by Ram Kishor Yadav, Thomas Girke, Sumana Pasala and Mingtang Xie. The 24-month research project was funded by a grant from the National Science Foundation.

Basic Nutrition

2009-08-17T21:06:00.000-07:00

Basic Nutrition
Jump to: Introduction : Protein : Carbohydrate : Dietary Fibre : Fats & Oils : Vitamins : Minerals

Introduction
Many people worry that when they stop eating meat and fish, they might be in danger of some nutritional deficiency. This is not the case as all the nutrients you need can easily be obtained from a vegetarian diet. In fact research shows that in many ways a vegetarian diet is healthier than that of a typical meat-eater.
Nutrients are usually divided into five classes: carbohydrates, proteins, fats (including oil), vitamins and minerals. We also need fibre and water. All are equally important to our well-being, although they are needed in varying quantities, from about 250g of carbohydrate a day to less than two micrograms of vitamin B12. Carbohydrate, fat and protein are usually called macro-nutrients and the vitamins and minerals are usually called micro-nutrients.
Most foods contain a mixture of nutrients (there are a few exceptions, like pure salt or sugar) but it is convenient to classify them by the main nutrient they provide. Still, it is worth remembering that everything you eat gives you a whole range of essential nutrients.
Meat supplies protein, fat, some B vitamins and minerals (mostly iron, zinc, potassium and phosphorous). Fish, in addition to the above, supplies vitamins A, D, and E, and the mineral iodine. All these nutrients can be easily obtained by vegetarians from other sources, as this Information Sheet shows.
Protein
Women need about 45g of protein a day (more if pregnant, lactating or very active), men need about 55g (more if very active). Evidence suggests that excess protein contributes to degenerative diseases. Vegetarians obtain protein from:
• Nuts: hazels, brazils, almonds, cashews, walnuts, pine kernels etc.
• Seeds: sesame, pumpkin, sunflower, linseeds.
• Pulses: peas, beans, lentils, peanuts.
• Grains/cereals: wheat (in bread, flour, pasta etc), barley, rye, oats, millet, maize (sweetcorn), rice.
• Soya products: tofu, tempeh, textured vegetable protein, veggieburgers, soya milk.
• Dairy products: milk, cheese, yoghurt (butter and cream are very poor sources of protein).
• Free range eggs.
You have may have heard that it is necessary to balance the complementary amino acids in a vegetarian diet. This is not as alarming as it sounds. Amino acids are the units from which proteins are made. There are 20 different ones in all. We can make many of them in our bodies by converting other amino acids, but eight cannot be made, they have to be provided in the diet and so they are called essential amino acids.
Single plant foods do not contain all the essential amino acids we need in the right proportions, but when we mix plant foods together, any deficiency in one is cancelled out by any excess in the other. We mix protein foods all the time, whether we are meat-eaters or vegetarians. It is a normal part of the human way of eating. A few examples are beans on toast, muesli, or rice and peas. Adding dairy products or eggs also adds the missing amino acids, eg macaroni cheese, quiche, porridge.
It is now known that the body has a pool of amino acids so that if one meal is deficient, it can be made up from the body's own stores. Because of this, we don't have to worry about complementing amino acids all the time, as long as our diet is generally varied and well-balanced. Even those foods not considered high in protein are adding some amino acids to this pool.
Carbohydrate
Carbohydrate is our main and most important source of energy, and most of it is provided by plant foods. There are three main types: simple sugars, complex carbohydrates or starches and dietary fibre.
The sugars or simple carbohydrates can be found in fruit, milk and ordinary table sugar. Refined sources of sugar are best avoided as they provide energy without any associated fibre, vitamins or minerals and they are also the main cause of dental decay.
Complex carbohydrates are found in cereals/grains (bread, rice, pasta, oats, barley, millet, buckwheat, rye) and some root vegetables, such as potatoes and parsnips. A healthy diet should contain plenty of these starchy foods as a high intake of complex carbohydrate is now known to benefit health. The unrefined carbohydrates, like wholemeal bread and brown rice are best of all because they contain essential dietary fibre and B vitamins.
The World Health Organisation recommends that 50-70% of energy should come from complex carbohydrates. The exact amount of carbohydrate that you need depends upon your appetite and also your level of activity. Contrary to previous belief a slimming diet should not be low in carbohydrates. In fact starchy foods are very filling relative to the number of calories that they contain.
Dietary Fibre
Dietary fibre or non-starch polysaccharide (NSP), as it is now termed, refers to the indigestible part of a carbohydrate food. Fibre can be found in unrefined or wholegrain cereals, fruit (fresh and dried) and vegetables. A good intake of dietary fibre can prevent many digestive problems and protect against diseases like colon cancer and diverticular disease.
Fats & Oils
Too much fat is bad for us, but a little is necessary to keep our tissues in good repair, for the manufacture of hormones and to act as a carrier for some vitamins. Like proteins, fats are made of smaller units, called fatty acids. Two of these fatty acids, linoleic and linolenic acids, are termed essential as they must be provided in the diet. This is no problem as they are widely found in plant foods.
Fats can be either saturated or unsaturated (mono-unsaturated or poly-unsaturated). A high intake of saturated fat can lead to a raised blood cholesterol level and this has been linked to heart disease. Vegetable fats tend to be more unsaturated and this is one of the benefits of a vegetarian diet. Mono-unsaturated fats, such as olive oil or peanut oil, are best used for frying as the poly-unsaturated fats, like sunflower or safflower oil are unstable at high temperatures. Animal fats (including butter and cheese) tend to be more saturated than vegetable fats, with the exception of palm oil and coconut oil.
Vitamins
Vitamin is the name for several unrelated nutrients that the body cannot synthesise either at all, or in sufficient quantities. The one thing they have in common is that only small quantities are needed in the diet. The main vegetarian sources are listed below:
Vitamin A (or beta carotene): Red, orange or yellow vegetables like carrots and tomatoes, leafy green vegetables and fruits like apricots and peaches. It is added to most margarines.
B Vitamins: This group of vitamins includes B1 (thiamin), B2 (riboflavin), B3 (niacin), B6 (pyridoxine), B12 (cyanocobalmin), folate, pantothenic acid and biotin.
All the B vitamins except B12 occur in yeasts and whole cereals (especially wheat germ), nuts & seeds, pulses and green vegetables.
Vitamin B12 is the only one that may cause some difficulty as it is not present in plant foods. Only very tiny amounts of B12 are needed and vegetarians usually get this from dairy produce and free range eggs. It is sensible for vegans and vegetarians who consume few animal foods to incorporate some B12 fortified foods in their diet. Vitamin B12 is added to yeast extracts, soya milks, veggieburgers and some breakfast cereals.
Vitamin C: Fresh fruit, salad vegetables, all leafy green vegetables and potatoes.
Vitamin D: This is vitamin is not found in plant foods but humans can make their own when skin is exposed to sunlight. It is also added to most margarines and is present in milk, cheese and butter. These sources are usually adequate for healthy adults. The very young, the very old and anyone confined indoors would be wise to take a vitamin D supplement especially if they consume very few dairy products.
Vitamin E: Vegetable oil, wholegrain cereals, eggs.
Vitamin K: Fresh vegetables, cereals and bacterial synthesis in the intestine.
Minerals
Minerals perform a variety of jobs in the body. Details of the some of the most important minerals are listed below:
Calcium: Important for healthy bones and teeth. Found in dairy produce, leafy green vegetables, bread, tap water in hard water areas, nuts and seeds (especially sesame seeds), dried fruits, cheese. Vitamin D helps calcium to be absorbed.
Iron: Needed for red blood cells. Found in leafy green vegetables, wholemeal bread, molasses, eggs, dried fruits (especially apricots and figs), lentils and pulses. Vegetable sources of iron are not as easily absorbed as animal sources, but a good intake of vitamin C will enhance absorption.
Zinc: Plays a major role in many enzyme reactions and the immune system. Found in green vegetables, cheese, sesame and pumpkin seeds, lentils and wholegrain cereals.
Iodine: Present in vegetables, but the quantity depends on how rich the soil is in iodine. Dairy products also have plenty of iodine. Sea vegetables are a good source of iodine for vegans.

Reproductive System

2009-08-14T00:28:00.000-07:00

Reproductive System

Introduction

Sexual reproduction is the process of producing offspring for the survival of the species, and passing on hereditary traits from one generation to the next. The male and female reproductive systems contribute to the events leading to fertilization. Then, the female organs assume responsibility for the developing human, birth, and nursing. The male and female gonads (testes and ovaries) produce sex cells (ova and sperm) and the hormones necessary for the proper development, maintenance, and functioning of the organs of reproduction and other organs and tissues.

The reproductive system comprises the reproductive organs. In the male, the organs include the testes, accessory ducts, accessory glands, and penis. In the female, the organs include the uterus, uterine tubes, ovaries, vagina, and vulva.

Male reproductive organs

The testes are paired reproductive organs in the scrotum, which hangs outside the human body. Normal sperm production requires the cooler outside temperature. Each testis contains coiled seminiferous tubules where sperm (male reproductive cells) production occurs. Between the seminiferous tubules are Leydig cells, clusters of endocrine (secretory) cells. Leydig cells produce androgens (sex hormones), mostly testosterone.

Each sperm cell has three parts: a head, middle piece, and tail. An acrosome at the head tip produces enzymes that help penetrate the female ovum (egg). During conception, chromosomes (genetic material) in the nucleus (cell control center) join with chromosomes in the ovum. The middle piece contains mitochondria, structures that provide energy for the sperm. The mitochondria are tightly spiraled around the axial filaments (contractile portion) of the flagellum (tail). Centrioles form the tail, which moves the sperm toward the ovum. An ejaculation (ejection of sperm from the penis) has 300 to 500 million sperm.

The accessory ducts store secretions from the testes and accessory glands and deliver secretions to the penis. The epididymis, a coiled tube next to each testis, receives sperm from the seminiferous tubules. The epididymis has three parts: a head, body, and tail. The epididymis stores sperm and propels it toward the penis. Smooth muscle contractions in the epididymis walls move sperm through the duct. As sperm pass through the epididymis, the sperm mature and receive nourishment.

The vas deferens is the dilated continuation of the epididymis. The vas deferens travels out of the scrotum and into the abdomen (gut cavity) through the inguinal canal. Once in the abdomen, the vas deferens passes behind the urinary bladder and expands to form an ampulla (expanded end part). Each ampulla joins with a seminal vesicle (an accessory gland) to form an ejaculatory duct. The vas deferens is the main sperm carrier. Its walls contain three layers of smooth muscle innervated by sympathetic nerves. Stimulation of these nerves propels sperm into the ejaculatory ducts. Here, the ampulla of the vas deferens and seminal vesicles meet and secretions from the seminal vesicles and sperm are stored. From this junction, the ejaculatory ducts pass through the prostate gland, where they receive more secretions, then join with the single urethra (tube through which sperm and urine pass out of body).

The urethra is the final section of the duct system. It passes from the urinary bladder and the ends of the ejaculatory ducts through the prostate gland and into the penis. The urethra receives secretions from the ejaculatory ducts, the prostate gland, and the bulbourethral glands (accessory glands). The urethra carries sperm through the penis during intercourse; during urination, urine passes through it. The urethra cannot execute both functions simultaneously. During ejaculation, a muscular sphincter (ring of muscle) closes off the bladder.

The accessory glands produce fluids that nourish and energize the sperm for the journey to the ovum. For example, during sexual excitement the seminal vesicles add secretions to the sperm in the ejaculatory duct. These secretions provide energy for the sperm and a neutralizing chemical that reduces vaginal acidity.

The prostate gland lies under the urinary bladder and surrounds the first part of the urethra. Its secretions also help neutralize vaginal acidity and make sperm motile (able to move).

The bulbourethral glands secrete a clear fluid that neutralizes the acidity of remaining urine in the urethra. When secretions of these glands combine with sperm, the result is seminal fluid, or semen. Only 1 percent of semen is sperm. The remainder contains fructose to nourish the sperm, an alkaline component to neutralize vaginal and urethral acidity, and salts and phospholipids, substances that make sperm motile.

The penis (male sexual organ) deposits semen into the vagina during sexual intercourse and carries urine through the urethra during urination. It contains erectile tissue that becomes engorged with blood during sexual excitement, resulting in an erection. The penis includes the shaft (tubular portion), glans (penis tip and sexual sensation center), and the prepuce, or foreskin (loose skin fold over glans). In a circumcision procedure, the prepuce is removed.

Female reproductive organs

The female reproductive system is more complex than that of the male. It produces ova (egg cells); nourishes, carries, and protects the developing embryo; and nurses the newborn after birth. The system structures are the ovary, uterine tubes, uterus, vagina, vulva, and mammary glands.

Ovaries, a pair of female gonads (sex organs), reside in the pelvic part of the abdomen on either side of the uterus. Ovaries produce ova and estrogen (female sex hormone).

At puberty onset, the menstrual (uterine) cycle, a series of cyclic changes to the endometrium (uterine lining) begins. The ovarian cycle, fluctuating levels of ovarian hormones in the blood, causes the menstrual cycle.

The ovarian and menstrual cycles begin each month when a follicle (developing ovum surrounded by a cluster of cells) develops in the ovary. The hypothalamus in the brain produces hormones that cause these cycles. The hypothalamus releases gonadotropin-releasing hormone (GnRH), which acts on the anterior pituitary gland. GnRH causes the pituitary to release two more hormones: follicle-stimulating hormone (FSH) and luteinizing hormone (LH). FSH causes the primary oocyte within the follicle to develop into a secondary oocyte. Development occurs through meiosis (cell division that reduces the chromosome number in the cell from 46 to 23). Each secondary oocyte completes this division only when sperm fertilizes it.

The developing follicle produces estrogen, which causes the endometrium to prepare to nourish a fertilized egg. Estrogen also inhibits pituitary gland production of FSH. The elevated estrogen level causes the anterior pituitary to release LH. This action causes ovulation, a process in which the follicle rapidly enlarges and releases the secondary oocyte. LH also causes the collapsed follicle to become the corpus luteum, an endocrine (secretory) body. The corpus luteum secretes estrogen and progesterone (hormone that stimulates endometrium thickening). These hormones complete the endometrium development and maintain the endometrium for 10 to 14 days.

Unless sperm fertilize the secondary oocyte, the corpus luteum begins to degenerate, dropping blood progesterone levels. Without progesterone to maintain the endometrial lining, the lining is shed with the degenerated oocyte approximately 14 days after ovulation.

After ovulation, estrogen and progesterone act in the bloodstream to inhibit anterior pituitary production of LH and FSH. This negative feedback control ensures that only one follicle develops each cycle. Each cycle lasts approximately 28 days.

The uterine tubes (oviducts or fallopian tubes) are paired tubes that receive the developing ovum from the ovary. The infundibulum end is beside the ovary; its fimbria (feathery structures) "sweep" the developing ovum into the tube. The ampulla, the middle part of the uterine tube, contains smooth muscle to move the egg. Cilia (inner wall little projections) also sweep the egg along the tube. The unfertilized ovum degenerates in the ampulla; the fertilized ovum resumes its journey to the uterus. The isthmus end of the uterine tube opens into the uterus.

The uterus is a hollow muscular organ in front of the rectum and behind the urinary bladder. The fundus is the wide upper portion. The body is the tapered middle part that ends at the cervix (junction between the vagina and uterus). The isthmus is the constricted region between the body and cervix. The round ligaments hold the uterus anteverted (inclined forward) over the urinary bladder.

The uterus has three layers. The outer serous layer forms ligaments that hold it to the pelvic walls. The middle muscular layer has three muscle layers used in labor to deliver a baby. The endometrium inner mucosal lining has two layers, the stratum functionalis and stratum basalis.

Every month the stratum functionalis is built up in response to estrogen secretion. It contains blood vessels and glands to nourish the fertilized ovum. Unless sperm fertilizes the secondary oocyte, the corpus luteum disintegrates into corpus albicans, and estrogen and progesterone secretion cease. Without these hormones, the endometrium breaks down and menstruation (expulsion of endometrial lining from the uterus through the vagina) occurs. After menstruation, progesterone and LH levels decrease. The inhibition of LH causes the anterior pituitary to secrete FSH, which stimulates development of another ovum. The monthly cycle begins again.

The vagina is a muscular tube from the uterus to outside the body. In some women, the hymen (thin tissue) partially covers the vaginal orifice. Initial sexual intercourse or other form of penetration ruptures the hymen. The vagina receives sperm from sexual intercourse, channels menstrual flow out of the body, and is a birth canal for the baby during childbirth. Normally collapsed, it can enlarge to accommodate an erect penis or a birth.

The vulva, external genitalia, includes the mons pubis, labia majora, labia minora, and clitoris. The mons pubis is a mound of fatty tissue at the junction of the thighs and torso. During puberty, pubic hair covers it. The labia majora are skin folds that form the vulva outer border. During puberty, pubic hair covers the labia majora, too. The labia minora are inner, smaller skin folds that surround the urethral and vaginal openings. The labia minora merge anteriorly to form the prepuce (foreskin) of the clitoris. This small erectile structure, comparable to the male penis, becomes engorged with blood during sexual excitement and is the female center of sexual sensation.

The mammary glands have 15 to 20 lobes of glandular tissue. The lobes contain lactiferous ducts that converge toward the nipple. These ducts dilate just before they reach the lactiferous sinus, then constrict again before passing out of the nipple through 15 to 20 openings.

The mammary glands are in the breasts. These glands overlie the pectoral muscles and are attached to them via fascia (connective tissue). The glands are connected to the skin by the suspensory ligaments of the breast. These glands are modified sweat glands that produce and secrete milk during the lactation process to feed the newborn. During pregnancy, high blood estrogen and progesterone levels stimulate lactation. The corpus luteum produces these hormones during early pregnancy; the placenta takes over later. The hormones stimulate the ducts and glands in the breasts, enlarging the breasts.

Development of sex cells

The formation of sex cells begins before birth; spermatozoa form in males and oocytes in females. Spermatogenesis (sperm cell production) occurs in the seminiferous tubules. Spermatogonia (stem cells) line these tubules at birth and contain 46 chromosomes (genetic material). After birth, spermatogonia continue to divide during mitosis. This cell division process produces two daughter cells with the same chromosome number (46) as the parent.

At puberty onset, some spermatozoa grow to become primary spermatocytes. These cells undergo meiosis, the cell division process that cuts back the number of chromosomes from 46 to 23. Each primary spermatocyte undergoes the first meiotic division to produce two secondary spermatocytes. Each secondary spermatocyte undergoes the second meiotic division to produce two spermatids. Each spermatid develops into a mature spermatozoon (sperm cell). In this way, meiosis produces millions of sperm every day.

Oogenesis is the formation of the ovum (female sex cells), which begin as hundreds of thousands of oogonia (stem cells) in the fetal ovaries. During prenatal development, the oogonia grow to become primary oocytes that contain 46 chromosomes. Each oocyte undergoes meiosis; at birth, oocytes are in prophase. During this first meiotic division, oocytes enter a resting phase that lasts until the oocyte resumes development during the ovarian cycle (puberty). The female is born with all the oocytes she will ever have.

Female Reproductive System

2009-08-14T00:16:00.000-07:00

Female Reproductive System
All living things reproduce. Reproduction — the process by which organisms make more organisms like themselves — is one of the things that sets living things apart from nonliving matter. But even though the reproductive system is essential to keeping a species alive, unlike other body systems, it's not essential to keeping an individual alive.
In the human reproductive process, 2 kinds of sex cells, or gametes, are involved. The male gamete, or sperm, and the female gamete, the egg or ovum, meet in the female's reproductive system to create a new individual.
Both the male and female reproductive systems are essential for reproduction. The female needs a male to fertilize her egg, even though it is she who carries offspring through pregnancy and childbirth.
Humans, like other organisms, pass certain characteristics of themselves to the next generation through their genes, the special carriers of human traits. The genes that parents pass along to their children are what make children similar to others in their family, but they are also what make each child unique. These genes come from the male's sperm and the female's egg, which are produced by the male and female reproductive systems.
About the Female Reproductive System
Most species have two sexes: male and female. Each sex has its own unique reproductive system. They are different in shape and structure, but both are specifically designed to produce, nourish, and transport either the egg or sperm.
Unlike the male, the human female has a reproductive system located entirely in the pelvis. The external part of the female reproductive organs is called the vulva, which means covering. Located between the legs, the vulva covers the opening to the vagina and other reproductive organs located inside the body.
The fleshy area located just above the top of the vaginal opening is called the mons pubis. Two pairs of skin flaps called the labia (which means lips) surround the vaginal opening. The clitoris, a small sensory organ, is located toward the front of the vulva where the folds of the labia join. Between the labia are openings to the urethra (the canal that carries urine from the bladder to the outside of the body) and vagina. Once girls become sexually mature, the outer labia and the mons pubis are covered by pubic hair.
A female's internal reproductive organs are the vagina, uterus, fallopian tubes, and ovaries.
The vagina is a muscular, hollow tube that extends from the vaginal opening to the uterus. The vagina is about 3 to 5 inches (8 to 12 centimeters) long in a grown woman. Because it has muscular walls, it can expand and contract. This ability to become wider or narrower allows the vagina to accommodate something as slim as a tampon and as wide as a baby. The vagina's muscular walls are lined with mucous membranes, which keep it protected and moist.
The vagina serves three purposes:
1.It's where the penis is inserted during sexual intercourse.
2.It's the pathway that a baby takes out of a woman's body during childbirth, called the birth canal.
3.It provides the route for the menstrual blood (the period) to leave the body from the uterus.
A thin sheet of tissue with one or more holes in it called the hymen partially covers the opening of the vagina. Hymens are often different from female to female. Most women find their hymens have stretched or torn after their first sexual experience, and the hymen may bleed a little (this usually causes little, if any, pain). Some women who have had sex don't have much of a change in their hymens, though.
The vagina connects with the uterus, or womb, at the cervix (which means neck). The cervix has strong, thick walls. The opening of the cervix is very small (no wider than a straw), which is why a tampon can never get lost inside a girl's body. During childbirth, the cervix can expand to allow a baby to pass.
The uterus is shaped like an upside-down pear, with a thick lining and muscular walls — in fact, the uterus contains some of the strongest muscles in the female body. These muscles are able to expand and contract to accommodate a growing fetus and then help push the baby out during labor. When a woman isn't pregnant, the uterus is only about 3 inches (7.5 centimeters) long and 2 inches (5 centimeters) wide.
At the upper corners of the uterus, the fallopian tubes connect the uterus to the ovaries. The ovaries are two oval-shaped organs that lie to the upper right and left of the uterus. They produce, store, and release eggs into the fallopian tubes in the process called ovulation. Each ovary measures about 1½ to 2 inches (4 to 5 centimeters) in a grown woman.
There are two fallopian tubes, each attached to a side of the uterus. The fallopian tubes are about 4 inches (10 centimeters) long and about as wide as a piece of spaghetti. Within each tube is a tiny passageway no wider than a sewing needle. At the other end of each fallopian tube is a fringed area that looks like a funnel. This fringed area wraps around the ovary but doesn't completely attach to it. When an egg pops out of an ovary, it enters the fallopian tube. Once the egg is in the fallopian tube, tiny hairs in the tube's lining help push it down the narrow passageway toward the uterus.
The ovaries are also part of the endocrine system because they produce female sex hormones such as estrogen and progesterone.
What the Female Reproductive System Does
The female reproductive system enables a woman to:
produce eggs (ova)
have sexual intercourse
protect and nourish the fertilized egg until it is fully developed
give birth
Sexual reproduction couldn't happen without the sexual organs called the gonads. Although most people think of the gonads as the male testicles, both sexes actually have gonads: In females the gonads are the ovaries. The female gonads produce female gametes (eggs); the male gonads produce male gametes (sperm). After an egg is fertilized by the sperm, the fertilized egg is called the zygote.
When a baby girl is born, her ovaries contain hundreds of thousands of eggs, which remain inactive until puberty begins. At puberty, the pituitary gland, located in the central part of the brain, starts making hormones that stimulate the ovaries to produce female sex hormones, including estrogen. The secretion of these hormones causes a girl to develop into a sexually mature woman.
Toward the end of puberty, girls begin to release eggs as part of a monthly period called the menstrual cycle. Approximately once a month, during ovulation, an ovary sends a tiny egg into one of the fallopian tubes.
Unless the egg is fertilized by a sperm while in the fallopian tube, the egg dries up and leaves the body about 2 weeks later through the uterus — this is menstruation. Blood and tissues from the inner lining of the uterus combine to form the menstrual flow, which in most girls lasts from 3 to 5 days. A girl's first period is called menarche.
It's common for women and girls to experience some discomfort in the days leading to their periods. Premenstrual syndrome (PMS) includes both physical and emotional symptoms that many girls and women get right before their periods, such as acne, bloating, fatigue, backaches, sore breasts, headaches, constipation, diarrhea, food cravings, depression, irritability, or difficulty concentrating or handling stress. PMS is usually at its worst during the 7 days before a girl's period starts and disappears once it begins.
Many girls also experience abdominal cramps during the first few days of their periods caused by prostaglandins, chemicals in the body that make the smooth muscle in the uterus contract. These involuntary contractions can be either dull or sharp and intense.
It can take up to 2 years from menarche for a girl's body to develop a regular menstrual cycle. During that time, her body is adjusting to the hormones puberty brings. On average, the monthly cycle for an adult woman is 28 days, but the range is from 23 to 35 days.
If a female and male have sex within several days of the female's ovulation, fertilization can occur. When the male ejaculates (when semen leaves a male's penis), between 0.05 and 0.2 fluid ounces (1.5 to 6.0 milliliters) of semen is deposited into the vagina. Between 75 and 900 million sperm are in this small amount of semen, and they "swim" up from the vagina through the cervix and uterus to meet the egg in the fallopian tube. It takes only one sperm to fertilize the egg.
About a week after the sperm fertilizes the egg, the fertilized egg (zygote) has become a multicelled blastocyst. A blastocyst is about the size of a pinhead, and it's a hollow ball of cells with fluid inside. The blastocyst burrows itself into the lining of the uterus, called the endometrium. The hormone estrogen causes the endometrium to become thick and rich with blood. Progesterone, another hormone released by the ovaries, keeps the endometrium thick with blood so that the blastocyst can attach to the uterus and absorb nutrients from it. This process is called implantation.
As cells from the blastocyst take in nourishment, another stage of development, the embryonic stage, begins. The inner cells form a flattened circular shape called the embryonic disk, which will develop into a baby. The outer cells become thin membranes that form around the baby. The cells multiply thousands of times and move to new positions to eventually become the embryo.
After approximately 8 weeks, the embryo is about the size of an adult's thumb, but almost all of its parts — the brain and nerves, the heart and blood, the stomach and intestines, and the muscles and skin — have formed.
During the fetal stage, which lasts from 9 weeks after fertilization to birth, development continues as cells multiply, move, and change. The fetus floats in amniotic fluid inside the amniotic sac. The fetus receives oxygen and nourishment from the mother's blood via the placenta, a disk-like structure that sticks to the inner lining of the uterus and connects to the fetus via the umbilical cord. The amniotic fluid and membrane cushion the fetus against bumps and jolts to the mother's body.
Pregnancy lasts an average of 280 days — about 9 months. When the baby is ready for birth, its head presses on the cervix, which begins to relax and widen to get ready for the baby to pass into and through the vagina. The mucus that has formed a plug in the cervix loosens, and with amniotic fluid, comes out through the vagina when the mother's water breaks.
When the contractions of labor begin, the walls of the uterus contract as they are stimulated by the pituitary hormone oxytocin. The contractions cause the cervix to widen and begin to open. After several hours of this widening, the cervix is dilated (opened) enough for the baby to come through. The baby is pushed out of the uterus, through the cervix, and along the birth canal. The baby's head usually comes first; the umbilical cord comes out with the baby and is cut after the baby is delivered.
The last stage of the birth process involves the delivery of the placenta, which is now called the afterbirth. After it has separated from the inner lining of the uterus, contractions of the uterus push it out, along with its membranes and fluids.
Problems of the Female Reproductive System
Your daughter may sometimes experience reproductive system problems. Below are some examples of disorders that affect the female reproductive system.
Problems of the Vulva and Vagina
Vulvovaginitis is an inflammation of the vulva and vagina. It may be caused by irritating substances (such as laundry soaps or bubble baths). Poor personal hygiene (such as wiping from back to front after a bowel movement) may also cause this problem. Symptoms include redness and itching in the vaginal and vulvar areas and sometimes vaginal discharge. Vulvovaginitis can also be caused by an overgrowth of Candida, a fungus normally present in the vagina.
Nonmenstrual vaginal bleeding is most commonly due to the presence of a vaginal foreign body, often wadded-up toilet paper. It may also be due to urethral prolapse, a condition in which the mucous membranes of the urethra protrude into the vagina and form a tiny, doughnut-shaped mass of tissue that bleeds easily. It can also be due to a straddle injury (such as when falling onto a beam or bicycle frame) or vaginal trauma from sexual abuse.
Labial adhesions, the sticking together or adherence of the labia in the midline, usually appear in infants and young girls. Although there are usually no symptoms associated with this condition, labial adhesions can lead to an increased risk of urinary tract infection. Sometimes topical estrogen cream is used to help separate the labia.
Problems of the Ovaries and Fallopian Tubes
Ectopic pregnancy occurs when a fertilized egg, or zygote, doesn't travel into the uterus, but instead grows rapidly in the fallopian tube. A woman with this condition can develop severe abdominal pain and should see a doctor because surgery may be necessary.
Endometriosis occurs when tissue normally found only in the uterus starts to grow outside the uterus — in the ovaries, fallopian tubes, or other parts of the pelvic cavity. It can cause abnormal bleeding, painful periods, and general pelvic pain.
Ovarian tumors, although they're rare, can occur. Girls with ovarian tumors may have abdominal pain and masses that can be felt in the abdomen. Surgery may be needed to remove the tumor.
Ovarian cysts are noncancerous sacs filled with fluid or semisolid material. Although they are common and generally harmless, they can become a problem if they grow very large. Large cysts may push on surrounding organs, causing abdominal pain. In most cases, cysts will disappear on their own and treatment is unnecessary. If the cysts are painful, a doctor may prescribe birth control pills to alter their growth, or they may be removed by a surgeon.
Polycystic ovary syndrome is a hormone disorder in which too many male hormones (androgens) are produced by the ovaries. This condition causes the ovaries to become enlarged and develop many fluid-filled sacs, or cysts. It often first appears during the teen years. Depending on the type and severity of the condition, it may be treated with drugs to regulate hormone balance and menstruation.
Ovarian torsion, or the twisting of the ovary, can occur when an ovary becomes twisted because of a disease or a developmental abnormality. The torsion blocks blood from flowing through the blood vessels that supply and nourish the ovaries. The most common symptom is lower abdominal pain. Surgery is usually necessary to correct it.
Menstrual Problems
A variety of menstrual problem can affect girls, including:
Dysmenorrhea is when a girl has painful periods.
Menorrhagia is when a girl has a very heavy periods with excess bleeding.
Oligomenorrhea is when a girl misses or has infrequent periods, even though she's been menstruating for a while and isn't pregnant.
Amenorrhea is when a girl has not started her period by the time she is 16 years old or 3 years after starting puberty, has not developed signs of puberty by age 14, or has had normal periods but has stopped menstruating for some reason other than pregnancy.
Toxic shock sindrome is caused by toxins released into the body during a type of bacterial infection that is more likely to develop if a tampon is left in too long. It can produce high fever, diarrhea, vomiting, and shock.
If you think your daughter may have symptoms of a problem with her reproductive system or if you have questions about her growth and development, talk to your doctor — many problems with the female reproductive system can be treated.

MALE REPRODUCTIVE SYSTEM

2009-08-14T00:10:00.000-07:00

MALE REPRODUCTIVE SYSTEM

All living things reproduce. Reproduction — the process by which organisms make more organisms like themselves — is one of the things that sets living things apart from nonliving things. But even though the reproductive system is essential to keeping a species alive, unlike other body systems it's not essential to keeping an individual alive.

In the human reproductive process, two kinds of sex cells, or gametes, are involved. The male gamete, or sperm, and the female gamete, the egg or ovum, meet in the female's reproductive system to create a new individual. Both the male and female reproductive system are essential for reproduction.

Humans, like other organisms, pass certain characteristics of themselves to the next generation through their genes, the special carriers of human traits. The genes parents pass along to their offspring are what make kids similar to others in their family, but they're also what make each child unique. These genes come from the father's sperm and the mother's egg, which are produced by the male and female reproductive systems.

Understanding the male reproductive system, what it does, and the problems that can affect it can help you better understand your son's reproductive health.

About the Male Reproductive System

Most species have two sexes: male and female. Each sex has its own unique reproductive system. They are different in shape and structure, but both are specifically designed to produce, nourish, and transport either the egg or sperm.

Unlike the female, whose sex organs are located entirely within the pelvis, the male has reproductive organs, or genitals, that are both inside and outside the pelvis. The male genitals include:

the testicles
the duct system, which is made up of the epididymis and the vas deferens
the accessory glands, which include the seminal vesicles and prostate gland
the penis

In a guy who has reached sexual maturity, the two testicles, or testes, produce and store millions of tiny sperm cells. The testicles are oval-shaped and grow to be about 2 inches (5 centimeters) in length and 1 inch (3 centimeters) in diameter. The testicles are also part of the endocrine system because they produce hormones, including testosterone. Testosterone is a major part of puberty in boys, and as a guy makes his way through puberty, his testicles produce more and more of it. Testosterone is the hormone that causes boys to develop deeper voices, bigger muscles, and body and facial hair, and it also stimulates the production of sperm.

Alongside the testicles are the epididymis and the vas deferens, which make up the duct system of the male reproductive organs. The vas deferens is a muscular tube that passes upward alongside the testicles and transports the sperm-containing fluid called semen. The epididymis is a set of coiled tubes (one for each testicle) that connects to the vas deferens.

The epididymis and the testicles hang in a pouch-like structure outside the pelvis called the scrotum. This bag of skin helps to regulate the temperature of testicles, which need to be kept cooler than body temperature to produce sperm. The scrotum changes size to maintain the right temperature. When the body is cold, the scrotum shrinks and becomes tighter to hold in body heat. When it's warm, the scrotum becomes larger and more floppy to get rid of extra heat. This happens without a guy ever having to think about it. The brain and the nervous system give the scrotum the cue to change size.

The accessory glands, including the seminal vesicles and the prostate gland, provide fluids that lubricate the duct system and nourish the sperm. The seminal vesicles are sac-like structures attached to the vas deferens to the side of the bladder. The prostate gland, which produces some of the parts of semen, surrounds the ejaculatory ducts at the base of the urethra, just below the bladder. The urethra is the channel that carries the semen to the outside of the body through the penis. The urethra is also part of the urinary system because it is also the channel through which urine passes as it leaves the bladder and exits the body.

The penis is actually made up of two parts: the shaft and the glans. The shaft is the main part of the penis and the glans is the tip (sometimes called the head). At the end of the glans is a small slit or opening, which is where semen and urine exit the body through the urethra. The inside of the penis is made of a spongy tissue that can expand and contract.

All boys are born with a foreskin, a fold of skin at the end of the penis covering the glans. Some boys are circumcised, which means that a doctor or clergy member cuts away the foreskin. Circumcision is usually performed during a baby boy's first few days of life. Although circumcision is not medically necessary, parents who choose to have their children circumcised often do so based on religious beliefs, concerns about hygiene, or cultural or social reasons. Boys who have circumcised penises and those who don't are no different: All penises work and feel the same, regardless of whether the foreskin has been removed.

What the Male Reproductive System Does

The male sex organs work together to produce and release semen into the reproductive system of the female during sexual intercourse. The male reproductive system also produces sex hormones, which help a boy develop into a sexually mature man during puberty

When a baby boy is born, he has all the parts of his reproductive system in place, but it isn't until puberty that he is able to reproduce. When puberty begins, usually between the ages of 10 and 14, the pituitary gland — which is located near the brain — secretes hormones that stimulate the testicles to produce testosterone. The production of testosterone brings about many physical changes. Although the timing of these changes is different for every guy, the stages of puberty generally follow a set sequence.

During the first stage of male puberty, the scrotum and testes grow larger.
Next, the penis becomes longer, and the seminal vesicles and prostate gland grow.
Hair begins to appear in the pubic area and later it grows on the face and underarms. During this time, a male's voice also deepens.

A male who has reached puberty will produce millions of sperm cells every day. Each sperm is extremely small: only 1/600 of an inch (0.05 millimeters long). Sperm develop in the testicles within a system of tiny tubes called the seminiferous tubules. At birth, these tubules contain simple round cells, but during puberty, testosterone and other hormones cause these cells to transform into sperm cells. The cells divide and change until they have a head and short tail, like tadpoles. The head contains genetic material (genes). The sperm use their tails to push themselves into the epididymis, where they complete their development. It takes sperm about 4 to 6 weeks to travel through the epididymis.

The sperm then move to the vas deferens, or sperm duct. The seminal vesicles and prostate gland produce a whitish fluid called seminal fluid, which mixes with sperm to form semen when a male is sexually stimulated. The penis, which usually hangs limp, becomes hard when a male is sexually excited. Tissues in the penis fill with blood and it becomes stiff and erect (an erection). The rigidity of the erect penis makes it easier to insert into the female's vagina during sexual intercourse. When the erect penis is stimulated, muscles around the reproductive organs contract and force the semen through the duct system and urethra. Semen is pushed out of the male's body through his urethra — this process is called ejaculation. Each time a guy ejaculates, it can contain up to 500 million sperm.

When the male ejaculates during intercourse, semen is deposited into the female's vagina. From the vagina the sperm make their way up through the cervix and move through the uterus with help from uterine contractions. If a mature egg is in one of the female's fallopian tubes, a single sperm may penetrate it, and fertilization, or conception, occurs.

This fertilized egg is now called a zygote and contains 46 chromosomes — half from the egg and half from the sperm. The genetic material from the male and female has combined so that a new individual can be created. The zygote divides again and again as it grows in the female's uterus, maturing over the course of the pregnancy into an embryo, a fetus, and finally a newborn baby.

Things That Can Go Wrong With the Male Reproductive System

Boys may sometimes experience reproductive system problems, including:

Disorders of the Scrotum, Testicles, or Epididymis
Conditions affecting the scrotal contents may involve the testicles, epididymis, or the scrotum itself.

Testicular trauma. Even a mild injury to the testicles can cause severe pain, bruising, or swelling. Most testicular injuries occur when the testicles are struck, hit, kicked, or crushed, usually during sports or due to other trauma. Testicular torsion, when one of the testicles twists around, cutting off its blood supply, is also a problem that some teen males experience, although it's not common. Surgery is needed to untwist the cord and save the testicle.
Varicocele. This is a varicose vein (an abnormally swollen vein) in the network of veins that run from the testicles. Varicoceles commonly develop while a boy is going through puberty. A varicocele is usually not harmful, although it can damage the testicle or decrease sperm production. Take your son to see his doctor if he is concerned about changes in his testicles.
Testicular cancer. This is one of the most common cancers in men younger than 40. It occurs when cells in the testicle divide abnormally and form a tumor. Testicular cancer can spread to other parts of the body, but if it's detected early, the cure rate is excellent. Teen boys should be encouraged to learn to perform testicular self-examinations.
Epididymitis is inflammation of the epididymis, the coiled tubes that connect the testes with the vas deferens. It is usually caused by an infection, such as the sexually transmitted disease chlamydia, and results in pain and swelling next to one of the testicles.
Hydrocele. A hydrocele occurs when fluid collects in the membranes surrounding the testes. Hydroceles may cause swelling in the scrotum around the testicle but are generally painless. In some cases, surgery may be needed to correct the condition.
Inguinal. When a portion of the intestines pushes through an abnormal opening or weakening of the abdominal wall and into the groin or scrotum, it is known as an inguinal hernia. The hernia may look like a bulge or swelling in the groin area. It can be corrected with surgery.

Disorders of the Penis

Disorders affecting the penis include:

Inflammation of the penis. Symptoms of penile inflammation include redness, itching, swelling, and pain. Balanitis occurs when the glans (the head of the penis) becomes inflamed. Posthitis is foreskin inflammation, which is usually due to a yeast or bacterial infection.
Hypospadias. This is a disorder in which the urethra opens on the underside of the penis, not at the tip.
Phimosis. This is a tightness of the foreskin of the penis and is common in newborns and young children. It usually resolves itself without treatment. If it interferes with urination, circumcision (removal of the foreskin) may be recommended.
Paraphimosis. This may develop when a boy's uncircumcised penis is retracted but doesn't return to the unretracted position. As a result, blood flow to the head of the penis may be impaired, and your son may experience pain and swelling. A doctor may use lubricant to make a small incision so the foreskin can be pulled forward. If that doesn't work, circumcision may be recommended.
Ambiguous genitalia. This occurs when a child is born with genitals that aren't clearly male or female. In most boys born with this disorder, the penis may be very small or nonexistent, but testicular tissue is present. In a small number of cases, the child may have both testicular and ovarian tissue.
Micropenis. This is a disorder in which the penis, although normally formed, is well below the average size, as determined by standard measurements.

If your son has symptoms of a problem with his reproductive system or he has questions about growth and sexual development, talk with your doctor — many problems with the male reproductive system can be treated.

Dead Bodies and Disease: The “Danger” That Doesn’t Exist

2009-08-14T00:00:00.000-07:00

Dead Bodies and Disease: The "Danger" That Doesn't Exist

Funeral industry members frequently claim that dead bodies are a source of contagion to the public, and that embalming is necessary to prevent the spread of disease. Some will also claim that unembalmed dead bodies must be buried in a casket and a vault to prevent “contamination” of groundwater. These assertions are not true. The myth of contagion from dead bodies is one of the most persistent of the American funeral industry, and it's important for journalists to know there is no evidence, peer-reviewed or otherwise, to justify it. In fact, there is overwhelming scientific evidence against it. This guide should help you separate funeral myth from fact.

It’s important to remember that this is not a matter of opinion, but of facts. "He said, she said" stories are not appropriate. We often see articles that read like this:

"John Q. funeral director says embalming helps prevent the spread of disease, but consumer advocates say this isn't so."

This is not an accurate way to present the issue. It's not just that consumer advocates “say it isn't so”; the Centers for Disease Control, the World Health Organization, and the Pan-American Health Organization have all published data backing up our position. By contrast, there are no studies showing a public health threat from unembalmed bodies. There is no evidence of rampant disease in the countries around the world (almost all of them) where embalming is seldom, if ever, practiced. In addition, we’ve never seen one instance where a funeral industry member provided a journalist with any evidence to support the claim that unembalmed corpses pose a health threat. Funeral Consumers Alliance, however, supports its position with scientific, peer-reviewed evidence. The next time a funeral industry member claims dead bodies are dangerous, ask for evidence and documentation.

Q: Isn’t embalming required by law?

A: Never routinely. Minnesota is the only state in the country that requires embalming for all public viewing (which is misguided in the extreme). New Hampshire requires a body to be embalmed after 24 hours of being “exposed to the public,” which is also misguided. No other state has such requirements. About half the states don’t require embalming under any circumstances, while others require embalming or refrigeration if the body isn’t buried with 24-48 hours.

Source: Caring for the Dead: Your Final Act of Love, by Lisa Carlson. A 640-page state by state guide to funeral and burial law for the consumer. While published in 1998, Funeral Consumers Alliance staff research indicates the above statement on embalming and state laws is still correct.

Q: Aren’t dead bodies full of dangerous bacteria that can make the living sick?

A: No, not usually. It’s important to know the difference between disease-causing microorganisms and the normal (if unpleasant) microorganisms that produce natural decay. To put it plainly, decomposition is a smell problem, not a health problem. Here’s a paragraph the journal Perpsectives in Health (published by the Pan-American Health Organization) that sums it up well:

“The microorganisms that are involved in decomposition are not the kind that cause disease, [Oliver] Morgan's article explains. And most viruses and bacteria that do cause disease cannot survive more than a few hours in a dead body. An apparent exception is the human immunodeficiency virus, HIV, which has been shown to live up to 16 days in a corpse under refrigeration.”

Source: Perspectives in Health, a publication of the PAHO, a division of the World Health Organization.

Q: But if HIV can live in the body after death, doesn’t that make an unembalmed body dangerous?

A: No. A dead person with HIV (or most other diseases) is no more dangerous to you than a living person with HIV. The same simple precautions that we use when coming into contact with bodily fluids from the living apply when handling the dead:

“There is no reason that an unembalmed dead human body should be infectious to anyone attending visitation or public services. Persons transporting and handling bodies or cutting into them may be vulnerable in rare instances, with little or no risk if proper precautions are taken. To refuse to present a body unembalmed because of public health risk is unfounded. On rare occasions of certain deaths resulting from contagious disease, our office may encourage placing a facemask on the decedent before and during transportation and containment, and disposing without embalming or viewing. In the event, however, it becomes necessary to hold a body for an extended period of time before public services can be held, arterial embalming is recommended. Riding on an airplane or a bus may be a public health risk; the presence of an un-embalmed body is not.”

Source: Dr. Lakshmanan Sathyavagiswaran, M.D., Chief Medical Examiner of Los Angeles, as quoted in Mortuary Management magazine, October, 2006.
It surprises many people to learn the U.S. and Canada are the only countries that routinely embalm their dead. Some members of religious and ethnic groups (Jews and Muslims, most prominently, but also some Amish communities and others) in this country stick to the traditional private care of the body by nonprofessionals. The British equivalent of the Centers for Disease Control wrote there’s no reason to interfere in these time-honored traditions:

“Some ethnic groups require that relatives and religious leaders carry out their own hygienic preparation and rituals. . . It seems unreasonable to restrict such activities unless an obvious hazard exists. The use of gloves and simple protective clothing by the funeral director's staff and anyone else who handles the bodies should be an acceptable and effective safety measure.”

Source: Communicable Disease Report, a publication of the Public Health Laboratory Service in Britain. Available at www.hpa.org.uk/CDR/archives/CDRreview/1995/cdrr0595.pdf

The US Centers for Disease Control has also stated:

“We have not at any point prescribed embalming as a method of protecting public health.”

Source: Bernadette Burden, spokeswoman for the Centers for Disease Control and Prevention (CDC) - Atlanta, Georgia, as quoted in Mortuary Management magazine, October, 2006 .

Q: But don’t dead bodies cause epidemics? What about all those reports of epidemics after earthquakes and tsunamis?

A: No. This is a myth that just won’t die, and the hysteria surrounding dead bodies makes reasonable people make unjustified decisions after natural disasters that distract them from real health concerns:

“The notion that dead bodies pose an urgent health threat in the aftermath of a disaster is one of several enduring myths about disasters and relief efforts that the Pan American Health Organization (PAHO) and the World Health Organization (WHO) have been trying to counter for nearly two decades. In 1986, PAHO produced a video titled "Myths and Realities of Natural Disasters" that debunked some of the most common misconceptions and explained how they exacerbate problems following a disaster. Yet 19 years later, many of these myths persist. Perhaps the most enduring and consequential of these myths is the idea that dead bodies cause epidemics.

‘Survivors are much more likely to be a source of disease outbreaks," says Jean-Luc Poncelet, chief of PAHO's Emergency Preparedness and Disaster Relief program.’”

Source: Perspectives in Health, Volume 10, no. 1, 2005, a publication of the PAHO. Available at:

Q: What about groundwater? Don’t decomposing corpses contaminate?

A: Not if the cemetery is properly situated away from an important aquifer. Decomposition is nature’s way of recycling the body’s elements, and we need to keep this in perspective. Humans are not different in death from other animals. Deer, raccoons, and livestock die in the open all the time. None of them are embalmed or placed in caskets or concrete vaults, yet we don’t lobby our city councils for mandatory taxidermy for wild animals or livestock. No municipal authorities rush to clean up roadkill (although we might wish them to, for aesthetic reasons) to “prevent the spread of disease.” Note also that no state law requires the use of a casket or a vault for burial. If leakage from buried bodies were a public health concern, we’d expect at least one state would have laws requiring some sort of containment of corpses underground, yet there are no such laws.

While it wouldn’t be wise to bury bodies very near a stream or water table, the natural microorganisms in the soil do a good job of breaking down and filtering the products of decomposition:

“Although there is some evidence of microbiological contamination in the immediate vicinity of cemeteries, the rapid attenuation of these microorganisms suggests that they pose little risk.”

Source: “Infectious disease risks from dead bodies following natural disasters.” Rev Panam Salud Publica. 2004, Volume 15, no. 5. A publication of the PAHO. Available at:

Q: Don’t caskets and vaults prevent leakage from dead bodies?

A: First, see above to understand why leakage usually doesn’t matter anyway. But no, caskets and vaults are notorious for cracking and allowing air, water, and other fluids to get in and out. Any honest cemetery worker will tell you there’s no way to know what condition the casket and vault will be in if the body must be exhumed, and that it’s common to have to drain gallons of water from a supposedly “sealed” casket.

A 1994 study by the Monument Builders of North America on how well or poorly caskets held up over time confirms the anecdotes cemetery workers have relayed to us. They found significant problems with caskets even in mausoleums, an environment presumably “gentler” to the casket than underground burial:

“MBNA found that the Catholic Cemetery Association was documenting an 86% failure rate or problems with wood and cloth-covered caskets, 62% for nonsealing metal, and 46% for ‘protective” or ‘sealer’ caskets. Even with the somewhat better results, the report states in bold print, ‘It is highly unlikely that such protective sealer metal caskets employ sufficient mechanisms to contain body fluids or gases.’”

Healthy Diets: How Whole Food Nutrition Helps Prevent Disease

2009-08-13T23:58:00.000-07:00

Is Distance Running A Dangerous Sport?

Taking part in a marathon is not easy and definitely not suitable for everyone because one needs to run for a distance of about 42 km. In October 2007, a 35-year-old police officer running in the Chicago Marathon collapsed and died. In Singapore, a 25-year-old army captain also died after finishing a half marathon in August 2007.

Does this mean that marathon is a dangerous sport? Before drawing any conclusion, let us hear what the experts have said about marathon.

In fact, statistics showed that sudden death during running a marathon is very rare. In Singapore, there is only one death in every 15,000 to 18,000 healthy runners each year. The more common one are ailments such as musculoskeletal and heat injuries, according to experts.

People with uncontrolled hypertension and ischemic heart disease should not take part in marathons. This is because unforeseen stresses from heat, dehydration and physical or psychological pressures could well strain the cardiovascular system. People suspected of other medical conditions should get a pre-race screen.

Once results of screening confirm one’s fitness for running marathon, he or she should then undergo adequate training. The runner should at least have completed a distance run of 30 to 32 km at some point during the training for a marathon. The purpose is to allow acclimatization to weather, testing the type of clothing need, knowing energy and fluid needs, and gauging body's limits.

Running for 42 km straight is very likely to wear out the body. The human body begins to experience fatigue as soon as the carbohydrate stores are depleted. Therefore, a high-carbohydrate meal should be taken before the big race to provided sufficient fluid and energy for a run. Meanwhile, do not try new food just before a race as this could cause gastrointestinal discomfort. Instead, opt for safe food choices such as bananas or power bars.

During the run, the runner should monitor his or her physical state because the day's temperature and humidity could also affect the body adversely. Under the hot weather, blood is diverted to the skin for heat dissipation. This, coupled with fluid loss from sweating, will affect the body's ability to deliver oxygen and energy to the muscles. Such disturbance of the body’s heat regulation would trigger the occurrence of heat stroke. The result could be fatal if multiple organ complications emerge.

Hence, the runner should be aware of such as high internal temperatures and significant changes in one's mental state. In addition, unusual chest pains or palpitations, disorientation or confusion could also indicate cardiac-related conditions and other injuries.

If runners could observe points mentioned above, they might minimize their risk of having fatal consequence during the marathon event.
Understanding Why Whole Foods are so Good for You
Understanding how whole food nutrition helps prevent disease is the purpose of this article. It is much easier to prevent almost any health problem than it ever is to attempt to treat it or cure it after it is already present. And it has become quite apparent that a critical part of helping your body do what it already knows how to do to stay healthy is by supplying it with plenty of whole food nutrition. Now, all that term means - whole food nutrition - is all of the nutrients that are present in the foods that we get from plants – fruits, vegetables, grains, nuts, berries, beans, etc. We all know from childhood that fruits and vegetables are good for us – the problem is that there aren't very many people who realize just how very dangerous it is NOT to eat these foods. We all probably have the feeling, “Yes, I need to eat fruits and vegetables and I might be a little better off if I eat some, but I’m ok right now” – that’s probably not true if you’re not eating these foods. It really is dangerous to not eat these – now why is this? This is because it is now understood that there is a process in the human body, that is a normal part of our metabolism, that determines one’s rate of aging and risk of disease and if that process is allowed to go along at a faster rate, then you age more rapidly and your risk of disease is much higher and your body has much more trouble healing problems that do occur – this process is called oxidative stress. All it means is that when oxygen is burned by the cells to produce energy, little by-products called free radicals are left over; these free radicals damage the cells and the contents of the cells and any substance in the body with which it comes in contact, essentially. And that damage determines rate of aging and risk of disease and how much trouble your body is having staying healthy.
Things We Do That Increase Risk
There are certain things we do in life that can increase risk – smoking is number one, emotional stress certainly does it because that speeds up metabolism. Physical stress does, too – including exercise because, if you think about it, when you exercise you burn more oxygen because your muscles need more to produce more energy and that actually produces more free radicals and without the proper protective nutrition, exercise can also speed up this damaging process.

There are essentially two major parts to this whole food nutrition. First of all these foods contain literally thousands of substances called phytochemicals or phytonutrients, just meaning they are occurring in plants, and they are also called micronutrients because they are there in such tiny amounts – micrograms for the most part – and a major part of this concept is that none of these micronutrients are substances that we need large amounts of in a day’s time. Rather, the body knows how to use these with a little bit of everything present because there is a tremendous interdependence among these nutrients; there’s a synergistic effect to having them all together, so it’s really important to take them in in that way and with it being literally tens of thousands of substances, there really is no other way to get it other than as it occurs in the food. Now the two major sections or divisions among these are: Number one is many of them participate in the normal metabolic processes of the cells – the biochemical reactions that make up the light and the activity of a cell and, therefore, of an organ and of the body. The other major part is a group called the antioxidants – this is a group of at least several hundred, if not several thousands, that all function together because they function in a sequence, at least groups of them do – they’ll function in a sequence where one works and only then can the next one work and so on down the line. The role of the antioxidants is to neutralize those harmful free radicals before they can cause the damage that increases your rate of aging and risk of disease. So it’s vital to have these nutrients and antioxidants all together. This is one of the major dangerous effects or results of not having whole food nutrition. We’re allowing that damaging process to go along at a much higher rate. Unfortunately, there really isn’t an alarm system in the body – not an obvious one - that tells you on Monday that you didn’t eat enough vegetables on Saturday. It is several years, at least, of this damaging process going along at a higher rate before the symptoms of a degenerative or chronic disease start to show up, like cancer, emphysema, heart disease, arthritis, kidney disease – all of our degenerative diseases are at least worsened by, if not caused by, this process of oxidative stress, so including enough whole food nutrition in the diet is an imperative aspect of staying well or preventing disease.

Can Colostrum Cure Chronic Hepatitis?

2009-08-13T23:39:00.000-07:00

Can Colostrum Cure Chronic Hepatitis?

Achlorhydra Autoimmune Active Chronic Hepatitis is a serious disease that can lead to hepatic cirrhosis characterized by liver cells becoming severely damaged. More popularly known as chronic hepatitis, this disease causes the liver to be inflamed for more than six months. Diagnosis is usually performed through biochemical tests, although a liver biopsy may be undertaken by the attending physician for a closer look.
According to the Gastro Resource Centre (GRC), the common cause of Achlorhydra Autoimmune Active Chronic Hepatitis is viral infections of the liver. The usual patients are young to middle-aged females who complain of severe fatigue and who may likewise be suffering from another autoimmune disease condition such as hyperthyroidism.
The Complexity of Chronic Hepatitis
As its complete name suggests, Achlorhydra Autoimmune Active Chronic Hepatitis is another one of those complex autoimmune diseases which are not only difficult or tricky to diagnose, but to treat as well. Autoimmune diseases are characterized by the human body fighting its own substances and tissues, as if these biological components were foreign, dangerous substances.
This overreaction of the human body is similar in the psychological realm to a condition known as paranoia, where the mind conjures a certain object or situation as threatening even when it is not.
It is now known that the toxicity of Achlorhydra Autoimmune Active Chronic Hepatitis is practically irreversible once it reaches the stage of cirrhosis. Luckily, anything before that is still reversible through a number of medical therapies.
The more tricky part of Achlorhydra Autoimmune Active Chronic Hepatitis is it does not display any observable symptoms until the disease has advanced considerably. In certain cases, symptoms may turn out to be so vague they can be mistaken for signs of aging or your average work-induced fatigue.
Colostrum: A Natural Fighter
Where Chronic Hepatitis has not yet developed into cirrhosis of the liver, colostrum may play a role in reversing the trend. Most mothers are familiar with this term; colostrum is mother's milk, naturally triggered by pregnancy. Family physicians are acutely aware that a human female's colostrum supply will become available one day after she gives birth.
Enter Hyper Immunized Colostrum
Recent development of what is called hyper immunized colostrum offers one possible antidote towards winning the autoimmunity battle. If the human body tries so much as to trigger an autoimmune response, antigens present in the enhanced colostrum may be able to block the attempt.
Experiments being conducted by a company called Immuron in Australia are pioneering in this area. Already, however, enhanced colostrum is showing promising signs of battling some forms of diabetes, influenza and a gastrointestinal component of the AIDS virus.
It may not be the cure for Achlorhydra Autoimmune Active Chronic Hepatitis just yet, but the early signs of enhanced colostrum winning against the autoimmune battle are definitely encouraging!

Basic Anatomy - Tissues & Organs

2009-08-13T23:38:00.000-07:00

Basic Anatomy - Tissues & Organs

There are many different types of cells in the human body. None of these cells function well on there own, they are part of the larger organism that is called - you.
Tissues
Cells group together in the body to form tissues - a collection of similar cells that group together to perform a specialized function. There are 4 primary tissue types in the human body: epithelial tissue, connective tissue, muscle tissue and nerve tissue.
1.Epithelial Tissue - The cells of epithelial tissue pack tightly together and form continuous sheets that serve as linings in different parts of the body. Epithelial tissue serve as membranes lining organs and helping to keep the body's organs separate, in place and protected. Some examples of epithelial tissue are the outer layer of the skin, the inside of the mouth and stomach, and the tissue surrounding the body's organs.
2.Connective Tissue - There are many types of connective tissue in the body. Generally speaking, connective tissue adds support and structure to the body. Most types of connective tissue contain fibrous strands of the protein collagen that add strength to connective tissue. Some examples of connective tissue include the inner layers of skin, tendons, ligaments, cartilage, bone and fat tissue. In addition to these more recognizable forms of connective tissue, blood is also considered a form of connective tissue.
3.Muscle Tissue - Muscle tissue is a specialized tissue that can contract. Muscle tissue contains the specialized proteins actin and myosin that slide past one another and allow movement. Examples of muscle tissue are contained in the muscles throughout your body.
4.Nerve Tissue - Nerve tissue contains two types of cells: neurons and glial cells. Nerve tissue has the ability to generate and conduct electrical signals in the body. These electrical messages are managed by nerve tissue in the brain and transmitted down the spinal cord to the body.

Organs

Organs are the next level of organization in the body. An organ is a structure that contains at least two different types of tissue functioning together for a common purpose. There are many different organs in the body: the liver, kidneys, heart, even your skin is an organ. In fact, the skin is the largest organ in the human body and provides us with an excellent example for explanation purposes. The skin is composed of three layers: the epidermis, dermis and subcutaneous layer. The epidermis is the outermost layer of skin. It consists of epithelial tissue in which the cells are tightly packed together providing a barrier between the inside of the body and the outside world. Below the epidermis lies a layer of connective tissue called the dermis. In addition to providing support for the skin, the dermis has many other purposes. The dermis contains blood vessels that nourish skin cells. It contains nerve tissue that provides feeling in the skin. And it contains muscle tissue that is responsible for giving you 'goosebumps' when you get cold or frightened. The subcutaneous layer is beneath the dermis and consists mainly of a type of connective tissue called adipose tissue. Adipose tissue is more commonly known as fat and it helps cushion the skin and provide protection from cold temperatures.

Musculoskeletal System

2009-08-12T23:17:00.000-07:00

Musculoskeletal system
Main articles: Musculoskeletal system, muscular system, and skeletal system
The human musculoskeletal system consists of the human skeleton, made by bones attached to other bones with joints, and skeletal muscle attached to the skeleton by tendons.

Anterior (frontal) view of the opened heart. White arrows indicate normal blood flow.
[edit] Cardiovascular system
Main articles: Cardiovascular system and Human heart
The cardiovascular system comprises the heart, veins, arteries and capillaries. The primary function of the heart is to circulate the blood, and through the blood, oxygen and vital minerals to the tissues and organs that comprise the body. The left side of the main organ (left ventricle and left atrium) is responsible for pumping blood to all parts of the body, while the right side (right ventricle and right atrium pumps only to the lungs.[2][3]The heart itself is divided into three layers called the endocardium, myocardium and epicardium, which vary in thickness and function.[4]
Reproductive system
Main article: Reproductive system
Human reproduction takes place as internal fertilization by sexual intercourse. During this process, the erect penis of the male is inserted into the female's vagina until the male ejaculates semen, which contains sperm, into the female's vagina. The sperm then travels through the vagina and cervix into the uterus or fallopian tubes for fertilization of the ovum.

The human male reproductive system is a series of organs located outside the body and around the pelvic region of a male that contribute towards the reproductive process. The primary direct function of the male reproductive system is to provide the male gamete or spermatozoa for fertilization of the ovum.
The major reproductive organs of the male can be grouped into three categories. The first category is sperm production and storage. Production takes place in the testes which are housed in the temperature regulating scrotum, immature sperm then travel to the epididymis for development and storage. The second category are the ejaculatory fluid producing glands which include the seminal vesicles, prostate, and the vas deferens. The final category are those used for copulation, and deposition of the spermatozoa (sperm) within the female, these include the penis, urethra, vas deferens and Cowper's gland.
The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vagina, which acts as the receptacle for the male's sperm, the uterus, which holds the developing fetus, and the ovaries, which produce the female's ova. The breasts are also an important reproductive organ during the parenting stage of reproduction.
The vagina meets the outside at the vulva, which also includes the labia, clitoris and urethra; during intercourse this area is lubricated by mucus secreted by the Bartholin's glands. The vagina is attached to the uterus through the cervix, while the uterus is attached to the ovaries via the fallopian tubes. At certain intervals, typically approximately every 28 days, the ovaries release an ovum, which passes through the fallopian tube into the uterus. The lining of the uterus, called the endometrium, and unfertilized ova are shed each cycle through a process known as menstruation

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2009-03-02T06:48:00.001-08:00

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